So-called online games have become popular, wherein a game system implemented on a server device provides game data to a plurality of terminal devices via a communication network, and the plurality of terminal devices simultaneously progress a game using the provided game data.
Some online games may provide functions for exchanging virtual in-game cards and items (e.g., weapons) between the players, so as to encourage interaction between players. One method of exchanging in-game items between players is discussed in Japanese Patent Application Publication No. 2009-187143 (“the '143 Publication”).